In many medical environments, a medical fluid is injected into a patient during diagnosis or treatment. One example is the injection of contrast media into a patient to improve CT, Angiographic, Magnetic Resonance or Ultrasound imaging, using a powered, automatic injector.
Injectors suitable for these and similar applications typically must use a relatively large volume syringe and be capable of producing relatively large flow rates and injection pressures. For this reason, injectors for such applications are typically motorized, and include a large, high mass injector motor and drive train. For ease of use, the motor and drive train are typically housed in an injection head, which is supported by a floor, wall, or ceiling mounted arm.
The injection head is typically mounted on the arm in a pivotal manner, so that the head may be tilted upward (with the syringe tip above the remainder of the syringe) to facilitate filling the syringe with fluid, and downward (with the syringe tip below the remainder of the syringe) for injection. Tilting the head in this manner facilitates removal of air from the syringe during filling, and reduces the likelihood that air will be injected into the subject during the injection process. Nevertheless, the potential for accidentally injecting air into a patient remains a serious safety concern.
In addition to the injection head discussed above, many injectors include a separate console for controlling the injector. The console typically includes programmable circuitry which can be used for automatic, programmed control of the injector, so that the operation of the injector can be made predictable and potentially synchronized with operations of other equipment such as scanners or imaging equipment.
Thus, at least part of the injection process is typically automatically controlled; however, the filling procedure, and typically some part of the injection procedure, are normally performed by an operator, using hand-operated movement controls on the injector head. Typically, the hand-operated movement controls include buttons for reverse and forward movement of the injector drive ram, to respectively fill and empty the syringe. In some cases, a combination of buttons is used to initiate movement of the ram or to control ram movement speed. The injector head also typically includes a gauge or display for indicating injection parameters to the operator, such as the syringe volume remaining, for the operator's use when controlling the injector head.
In many cardiology procedures, cardiologists often prefer to use hand-held syringes to administer contrast media to a patent whereby the cardiologist can “feel” the injection and carefully control the rate of injection as needed. Because a high pressure is required to push contrast media through a catheter, small hand syringes must be used if an operator desires to manually administer the contrast media. However, these small syringes must be refilled several times during the contrast injection procedure, thereby increasing the risk of introducing air into the syringe or catheter.
U.S. Pat. No. 6,221,045 to Duchon et al. discloses a hand-held remote which may be used to control the injection of contrast media with a powered injector. If an operator chooses to use a powered injector having conventional controls, the operator must rely on visual indicators from the injector to determine how to manipulate the control for optimum injection. The visual indicators typical of current injector systems do not provide operators with the physical sensing of the injection that they prefer. Thus, one drawback of current injector systems, including the hand-held control system of Duchon et al., is that they do not permit operators to physically sense the injections and thereby control the rate and volume of the injection.
Due to sterility requirements in medical environments, hand-held controls are typically provided as disposable items. Thus, another drawback of conventional hand-held controls which utilize electronic or digital signals to control the injections is that they are not disposable without prohibitive expense.
A need exists for a hand-held remote which may be used with a powered medical injector to control the injection of contrast media while providing tactile feedback to the operator and which solves various problems in the art, such as those mentioned above.